When a user is listening to an audio output from a wireless device, such as a phone conversation, music or an audio component of a multimedia content, the user may also hear ambient noise. Ambient noise may be produced by people, equipment, traffic, or even other multimedia devices nearby, and is undesirable. The goal of noise cancelation is to somehow reduce or remove the ambient noise so that the user hears only the desired audio output from the wireless device.
Current noise cancelation techniques may include a set of speakers and a set of microphones in each ear cup of a noise canceling headset. The microphones are typically positioned in proximity to the outside of the ear cups to detect the ambient noise, whereas the speaker may also be positioned on the inside of the ear cup to subtract the ambient noise from the intended audio that is also played into the ear on the inside of the ear cups. To do the processing, headphones may include a processor to receive the input from the ambient noise detecting microphones on the outside of the ear cup, then calculate the noise estimate, and then play back the inverted (or negative) version of the ambient noise from the speakers on the inside of the ear cup. The processor may also scale the noise estimate because there is inherent isolation from the outside of the ear cups to the inside, which reduces the level of ambient noise on the inside of the ear cups. Since this process takes some processing power from an electronic computation device, the noise canceling headphones may require batteries as well.